c172, c172-le, c172p, c172r, c172x - I don't have the energy to sort out
the dependencies so throw it all in.

We should try to sort them out and include just the C172p by default
-- in any case, you should be able to remove the c172-le, c172r and
c172x without any damage (I think that all the dependencies are
downwards on c172). Since that's three removed, it might be worth
including a Cherokee (pa28-161), since it is the other common
entry-level trainer at flight schools, and that way we'd have most
student pilots covered.

I think I agree with this. Lot's of aircraft depend on the availability
of the C172 so that one should be included. The pa28 is the next most
popular GA aircraft, so I would include that one also.

Now that we have an aircraft download page I think that should be all
that gets included.